Developing cartridge, process cartridge, and electrophotographic image forming apparatus

ABSTRACT

A developing cartridge detachably mountable to an image forming apparatus main body having main body side guide portions and a cartridge mounting portion, including: a developer containing portion; a developing roller for developing a latent image formed on a photosensitive member with developer; first cartridge side guide portions provided at one end and the other end in a longitudinal direction of the roller, for engaging with the main body side guide portions to regulate a movement locus of the cartridge when the cartridge is mounted to the main body; and protruding portions provided at one end and the other end in the longitudinal direction, wherein the cartridge is mounted to the main body in a mounting direction orthogonal to the longitudinal direction with the roller being a leading edge, and the protruding portions protrude on a downstream side further than the roller in the mounting direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electrophotographic image formingapparatus to which developing cartridges are detachably mountable.Further, the present invention relates to an electrophotographic imageforming apparatus to which process cartridges are detachably mountable.

Here, the electrophotographic image forming apparatus forms an image ona recording medium by using an electrophotographic image formingprocess. Then, examples of the electrophotographic image formingapparatus include, for example, an electrophotographic copying machine,an electrophotographic printer (for example, such as a color laser beamprinter and a color LED printer), a facsimile machine, and a wordprocessor.

In the process cartridge, at least one of a charging means, a developingmeans, and a cleaning means each serving as process means and anelectrophotographic photosensitive member are integrated into acartridge, which is detachably mountable to an apparatus main body. Notethat the charging means, the developing means, and the cleaning meanswhich act on the electrophotographic photosensitive member (hereinafter,referred to as a photosensitive member) are referred to as the processmeans. Note that, the process cartridge, which integrally includes thephotosensitive member and the developing means, is referred to as aso-called integral type. Further, the process cartridge, whichintegrally includes the photosensitive member and the process meansother than the developing means, is referred to as a so-calledseparation type.

The developing cartridge includes a developing roller, and contains adeveloper (toner) used to develop an electrostatic latent image(hereinafter, referred to as a latent image) formed on thephotosensitive member by the developing roller. Note that, in a case ofthe developing cartridge, the photosensitive member is provided in theapparatus main body, or in the so-called separation type processcartridge (in this case, the process cartridge has no developing means).

Further, the developing cartridge and the process cartridge aredetachably mounted onto an electrophotographic image forming apparatusmain body (hereinafter, referred to as an apparatus main body), andcontribute to an image forming process for forming an image on arecording medium.

Here, the developing cartridge and the process cartridge can be mountedto and detached from the apparatus main body by the user him/herself.For that reason, the maintenance of the apparatus main body can easilybe performed by the user him/herself.

2. Description of the Related Art

In an electrophotographic image forming apparatus, for forming a colorimage, a method of superimposing developer images (hereinafter, referredto as “toner images”) formed with, for example, developers (hereinafter,referred to as “toner”) of a yellow color, a magenta color, a cyancolor, and a black color is known. Further, a cartage system is widelyadopted, in which a developer containing portion (hereinafter, referredto as a toner containing portion) containing toner and a developingmember such as a developing roller are incorporated into a frame toobtain a unit (hereinafter, referred to as “developing cartridge”),whereby the toner and the developing roller can be replaced easily whenthey reach predetermined lives.

On the other hand, another cartridge system is also widely adopted, inwhich an electrophotographic photosensitive member and process meansthat acts thereon are integrated to obtain a unit (hereinafter, referredto as a process cartridge), and the photosensitive member and theprocess means can be replaced easily when they reach predeterminedlives.

Further, a method of superimposing toner images includes a 4-pass systemand a 1-pass system. According to the 4-pass system, developing devicesare disposed side by side with respect to one photosensitive member, andlatent images formed on the photosensitive member are successivelydeveloped by the respective developing devices to obtain toner images.Then, multiple toner images are superimposed on an intermediate transfermember to form a color image (see Japanese Patent Application Laid-OpenNo. 2001-117350). According to the 1-pass system, multiplephotosensitive members are disposed side by side and latent images onthe respective photosensitive members are developed to obtain tonerimages. Those toner images are successively transferred to a recordingmedium, whereby a color image is formed (see Japanese Patent ApplicationLaid-Open No. 2006-189737). As one photosensitive member and oneexposure unit can constitute the 4-pass system, the 4-pass system isdesirable for the reduction in cost and the downsizing of an apparatus.On the other hand, according to the 1-pass system, though multiplephotosensitive members and multiple exposure units are required, theprinting speed of a color image can be enhanced.

In recent years, a color electrophotographic image forming apparatus(hereinafter, referred to as an image forming apparatus) is becomingwidespread, and the needs of users are being diversified. Among them,cases where an image forming apparatus is used on a desktop areincreasing, and hence there is a demand for the downsizing of theapparatus.

On the other hand, as illustrated in Japanese Patent ApplicationLaid-Open No. 2001-117350, in an image forming apparatus, it is knownthat a developing cartridge is inserted in the apparatus main body witha developing roller being a leading edge. Further, as illustrated inJapanese Patent Application Laid-Open No. 2006-189737, in the imageforming apparatus, it is known to insert a process cartridge into theapparatus main body with a photosensitive member being a leading edge.

As the apparatus main body is being downsized, the space for mounting adeveloping cartridge and a process cartridge is also decreasing.Therefore, there is a demand for a technology that enables a developingcartridge and a process cartridge to be replaced easily even in a narrowspace. Particularly, in the case of a configuration in which adeveloping cartridge is inserted in the apparatus main body with adeveloping roller being a leading edge, the developing roller may comeinto contact with an adjacent developing cartridge mounted onto theapparatus main body. This contact may damage the developing roller.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a further downsizedimage forming apparatus.

Another object of the present invention is to provide an image formingapparatus and a developing cartridge which reduce the possibility inthat, when the developing cartridge is to be mounted onto a developingcartridge mounting portion, a developing roller of the developingcartridge to be mounted may come into contact with a member on theapparatus main body side. Herein, the member on the apparatus main bodyside may be an outer wall provided on the apparatus main body and/or anadjacent cartridge that has already been mounted on the cartridgemounting portion and/or the cartridge mounting portion.

Still another object of the present invention is to provide an imageforming apparatus and a developing cartridge that can reduce thepossibility of the damage of a developing roller at a time ofreplacement of the developing cartridge.

Still another object of the present invention is to provide an imageforming apparatus and a process cartridge that reduce the possibility inthat, when the process cartridge is to be mounted onto a processcartridge mounting portion, a photosensitive member of the processcartridge to be mounted may come into contact with a member on theapparatus main body side. Herein, the member on the apparatus main bodyside may be an outer wall provided on the apparatus main body and/or anadjacent cartridge that has already been mounted on the cartridgemounting portion and/or the cartridge mounting portion.

Still another object of the present invention is to provide an imageforming apparatus and a process cartridge that can reduce thepossibility of the damage of a photosensitive member at a time ofreplacement of a process cartridge.

In order to attain the above-mentioned objects, according to the presentinvention, a developing cartridge detachably mountable to anelectrophotographic image forming apparatus main body having a main bodyside guide portion and a developing cartridge mounting portion on whicha plurality of developing cartridges are detachably mountedside-by-side, the developing cartridge comprises: a developer containingportion for containing a developer; a developing roller for developingan electrostatic latent image formed on an electrophotographicphotosensitive member using the developer; a first developing cartridgeside guide portion provided at each of one end and the other end in alongitudinal direction of the developing roller, for engaging with themain body side guide portion to regulate a movement locus of thedeveloping cartridge when the developing cartridge is mounted to theelectrophotographic image forming apparatus main body; and a protrudingportion provided at each of the one end and the other end in thelongitudinal direction of the developing roller, wherein the developingcartridge is mounted to the electrophotographic image forming apparatusmain body in a mounting direction orthogonal to the longitudinaldirection of the developing roller, and is mounted to the developingcartridge mounting portion with the developing roller being a leadingedge, and the protruding portion protrudes on a downstream side of thedeveloping roller in the mounting direction.

Further, another aspect of the present invention relates to a processcartridge and an electrophotographic image forming apparatus.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an entire structural view of an electrophotographic imageforming apparatus of a 4-pass system.

FIG. 2 is a view illustrating a method of replacing a developingcartridge.

FIG. 3 is a perspective view of the developing cartridge.

FIG. 4A is a perspective view of a developing cartridge and an apparatusmain body. FIG. 4B illustrates a guide groove.

FIG. 5 is a schematic view illustrating a developing cartridge and aguide groove.

FIG. 6A is a perspective view illustrating a protruding portion of thedeveloping cartridge.

FIG. 6B is a perspective view illustrating a second guide portion of thedeveloping cartridge.

FIG. 7A is a perspective view illustrating a state in which a guidemember is at a protruding position.

FIG. 7B is a perspective view illustrating a state in which the guidemember is at a retracted position.

FIG. 8 is a partially enlarged view of the developing cartridge.

FIG. 9 is a view illustrating a guide groove and a protruding portion.

FIGS. 10A, 10B, 10C, and 10D are schematic views illustrating anoperation of a guide member and a cam when the developing cartridge ismounted.

FIGS. 11A, 11B, 11C, and 11D are schematic views illustrating anoperation of the guide member and the cam when the developing cartridgeis removed.

FIG. 12 is an entire structural view of an electrophotographic imageforming apparatus of a 1-pass system.

FIG. 13 is a view illustrating a state in which a tray member isremoved.

FIG. 14 is a perspective view illustrating a process guide groove and adeveloping guide groove.

FIG. 15A is a perspective view of a process cartridge.

FIG. 15B is a perspective view of a developing cartridge.

FIG. 16 is a perspective view illustrating a state when the processcartridge and the developing cartridge are mounted.

FIG. 17 is a view illustrating a state when the process cartridge andthe developing cartridge are mounted.

FIG. 18A is a perspective view illustrating a protruding portion of theprocess cartridge.

FIG. 18B is a perspective view illustrating a second process cartridgeguide of the process cartridge.

FIG. 19 is a perspective view illustrating a process cartridge, adeveloping cartridge, and a tray member.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, the embodiments according to the present invention will bedescribed with reference to the accompanying drawings. It should benoted that the shapes and relative arrangements of components describedin the embodiments do not intend to limit the scope of the presentinvention, unless otherwise specified.

Embodiment 1

(Color Electrophotographic Image Forming Apparatus)

A color electrophotographic image forming apparatus (hereinafter,referred to as an image forming apparatus) 200 of the present inventionwill be described with reference to FIG. 1. FIG. 1 is a cross-sectionalview of an image forming apparatus main body (hereinafter, referred toas an apparatus main body) of a 4-pass system. A photosensitive unit(hereinafter, referred to as a unit) 3 having an electrophotographicphotosensitive belt (hereinafter, referred to as a belt) 31 is disposedin a center portion of FIG. 1. Further, a charging roller (chargingmember) 4 and a scanner 2 that is a latent image forming means aredisposed below the unit 3. Further, a cassette 81 in which paper (sheet)82 as a recording medium is stacked is disposed below the scanner 2. Onthe right side of the unit 3, developing cartridge mounting portions 18(FIGS. 1 and 2) on which developing cartridges 5 (5Y, 5M, 5C, 5K) havingdeveloping rollers 51 (developing members) (51Y, 51M, 51C, 51K) aredetachably mounted are disposed. In FIG. 1, multiple developingcartridges 5 containing developers of different colors are mounted ontothe mounting portions 18. The mounting portions 18 are spaces fordetachably mounting the cartridges 5. The cartridges 5 mounted onto themounting portions 18 are pressed toward the unit 3 by the elastic forceof pressure springs (elastic members) 111 as pressing members disposedon the right side of the cartridges 5. That is, the developing rollers51 are urged toward the belt 31. Thus, the cartridges 5 mounted onto themounting portions 18 are positioned at image forming positions where thedeveloping rollers 51 come into contact with the belt 31. Further, onthe left side of the unit 3, a cleaning portion 6 having a cleaningblade (cleaning member) 61 for removing substances adhering to the belt31 is disposed. On the left side of the cleaning portion 6, a transportportion 8 for transporting the paper (recording medium) 82 is disposed.On the other hand, a transfer portion 7 having a transfer belt (anintermediate transfer member) 71 onto which a developer image(hereinafter, referred to as a toner image) formed on the belt 31 istransferred is disposed above the unit 3. Further, a fixing portion 9for fixing the toner image on the paper 82 is disposed above thetransfer portion 7. The apparatus main body 1 refers to a configurationof the image forming apparatus 200 with the cartridges 5 removedtherefrom. Examples of the recording medium include paper and an OHPsheet, on which an image is formed by the image forming apparatus 200.

Next, the configuration of each portion will be described in detail.

(Sheet Feed Portion)

The sheet feed portion 8 will be described with reference to FIG. 1. Thesheet feed portion 8 transports the paper 82 stacked the cassette 81 tothe transfer portion 7. A sheet feed roller 83 rotates in accordancewith the image forming operation of the apparatus main body 1, and feedsthe paper 82 stacked in the cassette 81 one by one. A registrationroller 84 performs a non-rotation operation for placing the paper 82 ina stationary standby state and a rotation operation for transporting thepaper 82 to the transfer portion 7 in a predetermined sequence, therebyregistering a toner image in the course of a transfer step with thepaper 82. Immediately after the paper 82 is transported, theregistration roller 84 suspends rotation. After the formation of a tonerimage on the transfer belt 71 is completed, the roller 84 startsrotation at a predetermined timing.

(Photosensitive Unit)

Next, the photosensitive unit 3 will be described with reference toFIG. 1. The unit 3 has a belt 31, a driving roller 32 for driving thebelt 31, opposed rollers 33 disposed at positions opposed to thedeveloping rollers 51 (51Y, 51M, 51C, 51K) of the respective colors, anda primary transfer opposed roller 34 disposed at a position opposed to aprimary transfer roller 72. The belt 31 has a photosensitive layer madeof an organic photoconductor on the surface of the belt 31 and issupported rotatably. The belt 31 rotates in the counterclockwisedirection by the driving roller 32 at a time of rotation. At a time ofan image forming operation, on the belt 31 subjected to a chargingtreatment by the charging roller 4, an electrostatic latent image isformed with laser light L irradiated from the scanner 2 in accordancewith image information. In this embodiment, though the belt 31 is used,a so-called photosensitive drum may be used as a latent image bearingmember. The photosensitive drum has a photosensitive layer on thesurface of a cylinder.

(Developing Cartridge)

Next, the developing cartridge 5 will be described with reference toFIG. 1. The cartridge 5 has a developer containing portion (hereinafter,referred to as a toner containing portions) 52 (52Y, 52M, 52C, 52K) forcontaining a developer (hereinafter, referred to as a toner), adeveloping roller 51, and a developing frame 53 (53Y, 53M, 53C, 53K) forsupporting the developing roller 51 rotatably and integrating the tonercontaining portion 52 therewith. The developing roller 51 rotates in theclockwise direction to carry toner (allow the toner to adhere thereto)at a time of the image forming operation. The carried (adhering) toneris developed in accordance with an electrostatic latent image of thebelt 31 in a portion in which the developing roller 51 and the roller 33are opposed to each other when a predetermined bias is applied to thedeveloping roller 51. Thus, a toner image is formed on the belt 31. Thedevelopment is conducted for each color, and in the case of forming afull-color image, in this embodiment, toner images are formed in theorder of a yellow color, a magenta color, a cyan color, and a blackcolor. In this embodiment, four cartridges are disposed side-by-side ina vertical direction with respect to the installation surface (notshown) of the apparatus 200. This arrangement of cartridges accords tothe arrangement corresponding to the shape of the belt 31. For example,if the belt 31 is set diagonally, the four cartridges 5 may be disposeddiagonally in accordance with the setting of the belt 31. Further, inthe case of using a photosensitive drum in place of the belt 31, fourcartridges are disposed in an arc shape in accordance with the shape ofthe photosensitive drum. The cartridge 5Y contains yellow toner in thetoner containing portion 52Y, and forms a yellow toner image. Thecartridge 5M contains magenta toner in the toner containing portion 52Mand forms a magenta toner image. The cartridge 5C contains cyan toner inthe toner containing portion 52C and forms a cyan toner image. Thecartridge 5K contains black toner in the toner containing portion 52Kand forms a black toner image. The respective cartridges 5 have the sameconfiguration except for containing toner of different colors.

(Transfer Portion)

Next, the transfer portion 7 will be described with reference to FIG. 1.The transfer portion 7 has a transfer belt 71, the primary transferroller 72, a secondary transfer opposed roller 73, a driving roller 74,a secondary transfer roller 75, and a transfer cleaner 76. At a time ofthe image forming operation, the belt 71 is rotated by the roller 74 inthe clockwise direction. The toner on the belt 31 is transferred to thetransfer belt 71 (primary transfer step) by a predetermined bias appliedto the transfer roller 72 in a primary transfer nip portion where theopposed roller 34 and the transfer roller 72 are opposed to each other.This operation is repeated to superimpose toner images of a yellowcolor, a magenta color, a cyan color, and a black color successively onthe transfer belt 71, whereby a full-color image is formed. The transferroller 75 is away from the transfer belt 71 while the primary transferstep is repeated. After four toner images are formed on the transferbelt 71, the transfer roller 75 is moved toward the opposed roller 73 ata predetermined timing to come into contact with the transfer belt 71.At this time, the paper 82 transported from the registration roller 84is sandwiched by a secondary transfer nip portion between the transferroller 75 and the opposed roller 73, and the toner image on the transferbelt 71 is transferred to the paper 82 (secondary transfer step) by theapplication of a predetermined bias to the transfer roller 75. Transfercleaner 76 is away from the transfer belt 71 while the primary transferstep is repeated. The cleaner 76 comes into contact with the transferbelt 71 at a predetermined timing after the trailing edge of the tonerimage on the transfer belt 71 passes through the cleaner 76 after thestart of the secondary transfer step. Then, residual toner that cannotbe transferred completely in the secondary transfer step is cleaned withthe cleaner 76.

(Cleaning Portion)

The cleaning portion 6 has a cleaning blade 61 (hereinafter, referred toas a blade) and a waste toner container 62. The toner image formed onthe belt 31 is transferred to the transfer belt 71 in the primarytransfer nip portion between the opposed roller 34 and the transferroller 72. The residual toner that has not been transferred is cleanedby the blade 61. The collected residual toner is contained in theremoved toner container (removed toner containing portion) 62.

(Fixing Portion)

The fixing portion 9 has a heating roller 91 and a pressure roller 92.When the toner image transferred to the paper 82 passes through a nipportion between the rollers 91 and 92, the toner image is fixed at apredetermined temperature and pressure.

(Delivery Portion)

The paper 82 with the toner image fixed thereon is delivered outside ofthe apparatus main body by delivery rollers 101 of the delivery portion10, and stacked on a stacking portion 102.

(Life of a Developing Cartridge)

The toner contained in the toner containing portion 52 is consumed bythe repetition of the image forming operation. Further, the developingroller 51 is degraded by the repetition of the image forming operation.When the developing roller 51 is degraded, the quality of an image to beoutput by the image forming operation may be degraded. That is, when theimage forming operation is repeated predetermined times, the developingcartridge 5 reaches the end of the service life thereof. If thedeveloping cartridge 5 is used longer than the life thereof, the imagequality may be degraded. When the cartridge 5 does not provide the imagequality that can satisfy a user any more, the cartridge 5 is replaced bya new cartridge 5, whereby a satisfactory image forming operation can beperformed.

(Guide Member)

FIG. 3 is a perspective view of the cartridge 5. As illustrated in FIG.3, guide members 54 as developing cartridge side guide portions areprovided at one end and the other end in a longitudinal direction of thedeveloping roller 51 supported rotatably by the developing frame 53. Inthis embodiment, the guide members 54 may be formed directly on theframe 53 or may be separate members. Further, the developing roller 51is partially exposed from the cartridge 5 (frame 53). The guide members54 are provided at one end and the other end in the longitudinaldirection (longitudinal direction of the developing roller 51) of thecartridge 5, and outside of the frame 53 in a transversal direction(direction orthogonal to the longitudinal direction of the developingroller 51) of the cartridge 5. A shaft 51 a of the developing roller 51is supported rotatably by the guide members 54 (frame 53). The guidemember 54 has a protruding portion 54 a extending in a mountingdirection X in which the cartridge 5 is mounted onto the apparatus mainbody 1 (the cartridge mounting portion 18). The protruding portion 54 aprotrudes in the mounting direction X from the developing roller 51.That is, the protruding portion 54 a protrudes toward the downstreamside of a leading edge 51 b of the developing roller 51 in the mountingdirection X. The mounting direction X is orthogonal to the longitudinaldirection (axial direction) of the developing roller 51. Further, theleading edge 51 b is a portion along the longitudinal direction on amost downstream side of the developing roller 51 in the mountingdirection X.

(Replacement of a Developing Cartridge)

Next, the replacement of the cartridge 5 will be described withreference to FIGS. 2 to 5. As illustrated in FIG. 2, an open/close cover(open/close member) 11 provided at the apparatus main body 1 is opened,and multiple cartridges 5 are detachably mounted onto the cartridgemounting portions 18 (18Y, 18M, 18C, 18K) with the developing rollers 51being a leading edge. The cover 11 rotates about a hinge 11 a. Thecartridge mounting portion 18 is provided in the apparatus main body 1.The respective cartridges 5 are detachably mountable to the cartridgemounting portions 18 while being lined up side by side in the verticaldirection. On the other hand, as illustrated in FIGS. 2 and 4A, theapparatus main body 1 is provided with guide grooves (main body sideguide portions) 12 (12Y, 12M, 12C, 12K). Each of the guide grooves 12regulates a movement locus of the cartridge 5 when a user mounts thecartridge 5 on the apparatus main body 1 (the mounting portion 18).Also, each of the guide grooves 12 regulates a movement locus of thecartridge 5 when a user removes the cartridge 5 from the apparatus mainbody 1 (the mounting portion 18). Further, each of the guide grooves 12are provided on inner walls 1 a of the apparatus main body 1. That is,the guide grooves 12 are provided in the mounting portion 18 so as to beopposed to each other at one end side and the other end side in adirection perpendicular to the mounting direction X. As illustrated inFIG. 4B, the guide grooves 12 are designed so as to be engaged with theguide members 54 when the cartridge 5 is mounted. In this embodiment, asillustrated in FIG. 3, a width h in a height direction of the guidemember 54 is set to be smaller than a width H in a height direction ofthe developing frame 53 (cartridge 5). However, the width h may be setto be the same as the width H in the height direction of the developingframe 53. In this case, the developing frame 53 is allowed to have afunction as a guide member.

Note that the movement locus refers to a movement path along which thecartridge 5 reaches the mounting portion 18 (a mounting position forperforming an image formation) after the guide members (cartridge sideguide portions) 54 are engaged with the guide grooves (main body sideguide portions) 12. In this embodiment, the main body side guideportions are the grooves 12. And, the cartridge side guide portions arethe guide members 54 that have an elongated shape in the mountingdirection in which the cartridges 5 are mounted onto the apparatus mainbody 1 and that protrude outside from the frames 53. Thus, while theguide members 54 are regulated by the guide grooves 12 in a verticaldirection, i.e., while the movement locus thereof is regulated, thecartridge 5 is guided into a predetermined mounting portion 18. However,this embodiment is not limited thereto. For example, the cartridge sideguide portion may be a groove or the main body side guide portion may bea protruding portion. Even in this case, the cartridge 5 is guided intothe predetermined mounting portion 18 while the cartridge 5 is regulatedin a vertical direction, i.e., the movement locus thereof is regulated.Further, for example, the cartridge side guide portion may be aprotruding portion, and the main body side guide portion may be aprotruding portion. In this case, while the protruding portion as acartridge side guide portion is supported by the protruding portion asthe main body side guide portion, the cartridge 5 is guided into thepredetermined mounting portion 18. In such a case, the cartridge 5 isguided into the predetermined mounting portion 18 while the downwardmovement thereof is regulated, i.e., the movement locus thereof isregulated. This also applied to the embodiments described later. Theframes 53 (53Y, 53M, 53C, 53K) are outer walls of the cartridges 5.

Hereinafter, a method of mounting the cartridge 5M will be described byway of example with reference to FIGS. 4A and 5. This also applies tothe other cartridges 5, and hence the description thereof is omitted.

As illustrated in FIG. 4A, when the cartridge 5M is to be mounted, thecartridges 5Y and 5C adjacent to the cartridge 5M have already beenmounted onto the apparatus main body 1 (the mounting portion 18).Therefore, the cartridge 5M is mounted toward the cartridge 5Y (frame53Y), the cartridge 5C (frame 53C), and an opening 1 b provided in anouter wall 1 c of the apparatus main body 1 (FIG. 4). First, asillustrated in FIG. 4A, guide members 54M and guide grooves 12M arealigned with each other with the developing roller 51M being the leadingedge, and the cartridge 5M is moved toward the opening 1 b. According tothis embodiment, in the case where the alignment has not been completedyet, the leading edges of the guide members 54M come into contact withthe outer wall 1 c of the apparatus main body 1 and the adjacentcartridges 5Y and 5C (frames 53Y and 53C) that have already beenmounted. Therefore, the cartridge 5M cannot be moved in the mountingdirection X any more. Note that the guide members 54M protrude forwardin the mounting direction X (on the downstream side in the mountingdirection) from the leading edge 51 b of the developing roller 51M.Therefore, the developing roller 51M does not come into contact with theouter wall 1 c of the apparatus main body 1 and the cartridges 5Y and5C. Thus, according to this embodiment, the developing roller 51M can beprevented from being damaged. That is, according to this embodiment, theguide members 54 M are provided so as to have a protrusion length whichis capable of preventing the developing roller 51M from coming intocontact with the members on the side of the main body 1 when thecartridge 5M is to be mounted onto the apparatus main body 1 while theabove-mentioned alignment has not been completed yet. The guide members54M are provided at positions where they can prevent the developingroller 51M from coming into contact with the members on the side of themain body 1 at one end side and the other end side of the developingroller 51M. Herein, examples of the members on the side of the apparatusmain body 1 include the inner wall 1 a and the outer wall 1 c providedon the apparatus main body 1 and/or the adjacent cartridges that havealready been mounted onto the cartridge mounting portions 18 and/or thecartridge mounting portions 18. The other cartridges 5 also have thesame configurations as the cartridge 5M.

As illustrated in FIG. 5, when the cartridge 5M is inserted into theopening 1 b, first, the guide members 54M and the guide grooves 12M areengaged with each together. The cartridge 5M is further inserted intothe apparatus main body 1 as it is. Then, when the developing roller 51Mreaches the opening 1 b, the movement locus at a time of mounting of thecartridge 5M is regulated by the engagement between the guide members54M and the guide grooves 12M. The cartridge 5M is further moved towardthe inner part of the apparatus main body 1. Thus, the cartridge 5M canbe mounted onto the mounting portion 18M without bringing the developingroller 51M into contact with the adjacent cartridge 5Y (frame 53Y) andcartridge 5C (frame 53C). Note that when the cartridge 5M is removedfrom the apparatus main body 1, the operation opposite to theabove-mentioned operation may be performed.

While the developing roller 51M passes through the opening 1 b, theguide members 54M and the guide grooves 12M are engaged with each other.Thus, when the cartridge 5M is removed from the apparatus main body 1,the developing roller 51M does not come into contact with the inner wall1 a and the cartridges 5Y, 5C (frames 53Y, 53C). This can also preventthe damage of the developing roller 51M. Further, even in the case wheretoner adheres to the surface of the developing roller 51M, thecartridges 5Y, 5C (frames 53Y, 53C) can be prevented from beingcontaminated with the toner.

As described above, according to this embodiment, even if the opening 1b is made smaller so as to realize the downsizing of the image formingapparatus 200, the developing roller 51 is not damaged or the peripherythereof is not contaminated with toner. Thus, the cartridge 5 can bereplaced smoothly.

In this embodiment, the guide members 54 have protruding portions 54 aprotruding forward in the mounting direction X (downstream side in themounting direction X) further than the developing roller 51. However, asillustrated in FIG. 6A, protruding portions 55 may be provided on thecartridge 5 (frame 53). The protruding portions 55 are disposed so as toprotrude on the downstream side in the mounting direction X (forward inthe mounting direction X) further than the developing roller 51. Whenthe cartridge 5 is to be mounted onto the apparatus main body 1(mounting portion 18), even if the cartridge 5 is inserted in theapparatus main body 1 while the guide grooves (main body side guideportions) 12 and the guide members (first developing cartridge sideguide portions) 54 are not aligned, the protruding portions 55 come intocontact with the inner wall 1 a and the outer wall 1 c of the apparatusmain body, and the adjacent cartridges. Thus, according to thisembodiment, the developing roller 51 can be prevented from beingdamaged, and toner can be prevented from dropping from the developingroller 51. Further, the protruding portions may be provided with a guidefunction of being engaged with the guide grooves 12 and regulating themovement locus of the cartridge 5.

Further, as illustrated in FIG. 6B, the guide members 54 may be providedwith second guide portions 54 a as protruding portions that protrudefurther on the downstream side (forward) in the mounting direction X,further than the leading edge 51 b of the developing roller 51. Forexample, in the frame 53, protruding portions (second developingcartridge side guide portions) 54 a may be provided at one end side andthe other end side in the longitudinal direction of the developingroller 51. In the embodiment illustrated in FIG. 3, the protrudingportions 54 a and the guide members 54 are integrated. However, asillustrated in FIG. 6B, the protruding portions 54 a may be providedseparately from the guide members 54. In the case of those embodiments,the protruding portions 54 a have a function as the second guideportions for being engaged with the guide grooves (main body side guideportions) 12 to guide the cartridge 5.

Note that, the protrusion length of the protruding portion 54 aprotruding further than the leading edge 51 b to the downstream side(forward) in the mounting direction X, and the width h of the protrudingportion 54 a may be determined appropriately considering, for example,the curvature of the developing roller 51.

Embodiment 2

Next, Embodiment 2 will be described. In this embodiment, guide members(developing cartridge side guide portions) 56 of the cartridge 5 aremovable. The configuration of the apparatus main body is the same asthat in Embodiment 1, and hence the description thereof is omitted.

(Developing Frame)

As illustrated in FIG. 8, the frame 53 is provided with a developingbias electric contact (hereinafter, referred to as a developingelectrode) 532 for receiving a developing bias to be applied to thedeveloping roller 51 from the apparatus main body 1. The frame 53 has(supports) the developing roller 51 and the toner containing portion 52in an integrated manner. The guide members (developing cartridge sideguide portions) 56 are engaged with the guide grooves (main body sideguide portions) 12 to regulate the movement locus of the cartridge 5when the cartridge 5 is mounted and detached from the apparatus mainbody 1. The frame 53 has a lock hole 531 that is a part of a lockingmember for locking the guide member 56 at a retracted position P2. Thelock hole 531 is provided on the upstream side of the guide member 56 inthe mounting direction X.

(Guide Member)

As illustrated in FIGS. 7A and 7B, the guide members 56 are movable inthe mounting direction X. Herein, the mounting direction X refers to atransversal direction of the cartridge 5, which intersects with (isorthogonal to) the longitudinal direction of the developing roller 51.FIG. 7A illustrates the state (hereinafter, referred to as a protrudingposition P1) in which the guide members 56 protrude on the downstreamside in the mounting direction X further than the leading edge 51 b ofthe developing roller 51, and FIG. 7B illustrates the state(hereinafter, referred to as a retracted position P2) in which theleading edges of the guide members 56 are retracted on the upstream sidein the mounting direction X further than the leading edge 51 b of thedeveloping roller 51. As illustrated in FIG. 8, the guide member 56 isprovided with a guide cam 561, a cam spring (elastic member) 562, and aguide spring (elastic member) 563 that is an urging member of the guidemember 56. Further, as illustrated in FIG. 8, when the guide member 56is disposed at the protruding position P1, the developing electrode 532is covered with a cover portion 56 a of the guide member 56. Thisprotects the electrode 532. The cover portion 56 a serves as aprotruding portion. When the cartridge 5 is outside of the apparatusmain body 1, the guide member 56 is placed at the protruding positionP1. When the guide member 56 is placed at the protruding position P1,the protruding portion 56 a as the cover portion protrudes on thedownstream side in the mounting direction X further than the leadingedge 51 b of the developing roller 51. The guide cam 561 is supportedpivotally about a rotation center 561 a, and is urged in thecounterclockwise direction by the elastic force of the spring 562. Oneend portion of the spring 563 is connected to one end spring attachmentportion 53 a of the developing frame 53, and the other end portion ofthe spring 563 is connected to the other end spring attachment portion56 b of the guide member 56. The guide member 56 is urged elasticallyfrom the retracted position P2 to the protruding position P1 by theelastic force of the spring 563. The cam 561 has a first abuttingportion 561 b, a second abutting portion (locking portion) 561 c, and athird abutting portion (lock releasing portion) 561 d. As illustrated inFIG. 8, when the guide member 56 is placed at the protruding positionP1, the second abutting portion 561 c comes into contact with a wallsurface 53 b of the developing frame 53. Therefore, even if the elasticforce (urging force) of the spring 562 is exerted, the cam 561 cannotpivotally move in the counterclockwise direction any more. However, whenthe guide member 56 moves to the retracted position P2 as illustrated inFIG. 7B, the second abutting portion 561 c is pulled in the lock hole531. Then, by the elastic force of the spring 562, the cam 561 canpivotally move in the counterclockwise direction. When the secondabutting portion 561 c is engaged with the lock hole 531, the guidemember 56 is locked at the retracted position P2. When the cam 561 ispivotally rotated in the clockwise direction from this state to releasethe engagement between the second abutting portion 561 c and the lockhole 531, the lock of the guide member 56 is released. Then, by theelastic force of the spring 563, the guide member 56 moves from theretracted position P2 to the protruding position P1. That is, the guidemember 56 is movable from the protruding position P1 to the retractedposition P2, and is urged to the protruding position P1 by the elasticforce of the spring 563. Further, the guide member 56 can be locked atthe retracted position P2 and unlocked by the cam 561, the spring 562,and the lock hole 531. Further, when the guide member 56 is positionedat the protruding position P1 as illustrated in FIG. 7A, the electrode532 is protected by the cover portion 56 a of the guide member 56. Thedeveloping electrode 532 is configured to be exposed from the coverportion 56 a when the guide member 56 is positioned at the retractedposition P2 as illustrated in FIG. 7B.

(Guide Groove)

Further, as illustrated in FIG. 9, each of the guide grooves 12 has aprotruding portion 121 as an engagement portion to be engaged with theguide cam 561. Further, each of the guide grooves 12 has an electriccontact (body side electric contact) 122 on the apparatus main body sidefor applying a predetermined bias to the developing roller 51.

(Operation of a Guide Member at a Time of Mounting)

Next, the operations of the guide member 56 and the guide cam 561 whenthe cartridge 5 is mounted onto the apparatus main body 1 (mountingportion 18) are described with reference to FIGS. 10A to 10D. Note thatFIG. 10A illustrates the state in which the cartridge 5 begins to bemounted onto the mounting portion 18 (apparatus main body 1). Themounting operation proceeds as illustrated in FIGS. 10B and 10C, andFIG. 10D illustrates a state in which the mounting operation iscompleted.

First, as illustrated in FIG. 10A, when the cartridge 5 is mounted ontothe apparatus main body 1, the guide members 56 and the guide grooves 12of the apparatus main body 1 are aligned, and then, the cartridge 5 isinserted into the apparatus main body 1. At this time, because theelectrode 532 is covered with the cover portion 56 a of the guide member56, the electrode 532 results in being protected. The cartridge 5 isfurther inserted into the mounting portion 18 to go into the stateillustrated in FIG. 10B, in which the first abutting portion 561 b(abutted portion) of the cam 561 and an abutting portion 121 b of theprotruding portion 121 provided in the guide groove 12 come into contactwith each other. At this time, as the cam 561 is pivotally supported, amoment is generated in the counterclockwise direction. However, thesecond abutting portion 561 c of the cam 561 comes into contact with thewall surface 53 b of the developing frame 53. Therefore, the cam 561cannot be rotated. Thus, when the cartridge 5 is inserted into themounting portion 18 as it is, the other portions of the cartridge 5enter the mounting portion 18 while the guide member 56 remainsstationary in this state. When the state illustrated in FIG. 100 isobtained, the second abutting portion 561C is pulled in the lock hole531 provided in the developing frame 53. Then, the cam 561 is rotated inthe counterclockwise direction, and the state represented by a chaindouble-dashed line illustrated in FIG. 100 becomes the state representedby a solid line. At this time, the first abutting portion 561 b isreleased from the abutting portion 121 b of the protruding portion 121of the guide groove 12. However, the guide member 56 remains locked atthis position by the cam 561. At this time, the guide member 56completes the movement at the retracted position, and the electrode 532is exposed from the cover portion 56 a of the guide member 56. If thecartridge 5 is mounted onto the mounting portion 18 as it is, asillustrated in FIG. 10D, the electrode (cartridge side electric contact)532 and the electric contact (body side electric contact) 122 comes intocontact with each other. Then, as illustrated in FIG. 1, the mountingoperation of the cartridge 5 is completed when the cover 11 is closed.At this time, the cartridge 5 is pressed in a direction of the belt 31by the elastic force of the pressure spring (elastic member) 111.However, as described in this embodiment, the guide member 56 remainslocked at the retracted position. Therefore, the urging force urging theguide member 56 in a direction of the protruding position by the elasticforce of the spring 563 is not applied to the developing roller 51.Thus, by the elastic force of the spring 111, the developing roller 51can be pressed against the belt 31 at an appropriate pressure.

(Operation of a Guide Portion at a Time of Removal)

Next, the operations of the guide member 56 and the cam 561 when thecartridge 5 is removed from the main body 1 (mounting portion 18) willbe described with reference to FIGS. 11A to 11D. The cartridge 5 isremoved from the main body 1 in the order of FIGS. 11A, 11B, 11C, and11D. First as illustrated in FIG. 2, the cover 11 is opened, and thecartridge 5 is pulled out from the main body 1. At this time, asillustrated in FIG. 11A, the guide member 56 is pulled out while beinglocked at the retracted position. Then, as illustrated in FIG. 11A, thethird abutting portion (lock releasing portion) 561 d of the cam 561comes into contact with an inclined surface (engagement portion) 121 aof the protruding portion 121. When the cartridge 5 is further pulledout of the main body 1 (mounting portion 18), as illustrated in FIG.11B, the third abutting portion (lock releasing portion) 561 d runs uponthe inclined surface (engagement portion) 121 a. The cam 561 rotates inthe clockwise direction, and the second abutting portion 561 c is pulledout from the lock hole 531. That is, at this moment, the guide member 56is released from the state of being locked at the retracted position.That is, the third abutting portion (lock releasing portion) 561 d isengaged with the inclined surface (engagement portion) 121 a provided onthe guide groove (main body side guide portion) 12 when the cartridge 5is removed from the mounting portion 18, whereby the lock of the secondabutting portion (locking portion) 561 c is released. Thus, the guidemember 56 moves toward the protruding position by the elastic force ofthe spring 563. Then, as illustrated in FIG. 11C, the guide member 56moves to a position where the first abutting portion 561 c of the cam561 comes into contact with the abutting portion 121 b of the protrudingportion 121. Further, as illustrated in FIG. 11D, when the cartridge 5is pulled out, the guide member 56 is moved to the protruding positionby the elastic force of the spring 563. The cover portion 56 a of theguide member 56 covers the electrode 532. The movement locus of thecartridge 5 is regulated by the engagement between the guide member 56and the guide groove 12. Thus, the cartridge 5 can be removed from themain body 1 without bringing the developing roller 51 into contact withthe adjacent cartridge 5 and the like.

In Embodiment 1 described above, the guide member 54 is of a fixed type.Therefore, when the cartridge 5 is mounted onto the main body 1, asillustrated in FIG. 5, the leading edge of the guide member 54, i.e.,the protruding portion 54 a enters the side surface of the unit 3. Onthe other hand, as in this embodiment, when the mounting of thecartridge 5 on the main body 1 is completed, the guide member 56 isretracted to the retracted position P2 as illustrated in FIG. 7B. Inthis portion, for example, a driving portion for driving the unit 3, anelectrode for applying a bias, and the like can be disposed. Thus, theentire apparatus can further be downsized.

That is, according to this embodiment, the guide member 56 has aprotrusion length that is capable of preventing the developing roller 51from coming into contact with the members on the main body 1 side in thecase where the cartridge 5 is mounted onto the apparatus main body 1under the condition that the above-mentioned alignment has not beenperformed. The guide members 56 are provided at one end side and theother end side of the developing roller 51 so as to prevent thedeveloping roller 51 from coming into contact with the members on themain body 1 side. Herein, examples of the members on the apparatus mainbody 1 side include the inner wall 1 a and the outer wall 1 c providedon the apparatus main body 1 and/or the adjacent cartridges that havealready been mounted onto the cartridge mounting portions 18 and/or thecartridge mounting portions 18.

Embodiment 3

This embodiment relates to a color electrophotographic image formingapparatus of a 1-pass system. The image forming apparatus of the 1-passsystem has image forming portions respectively corresponding to a yellowcolor, a magenta color, a cyan color, and a black color, and forms acolor image by superimposing those colors successively. Compared withthe image forming apparatus of the 4-pass system described inEmbodiments 1 and 2, the image forming apparatus of the 1-pass systemhas an advantage in that color images can be output at a high speed.

Next, Embodiment 3 will be described. Note that the same referencenumerals as those in Embodiments 1 and 2 described above denote elementshaving the same functions as those therein, and hence the descriptionthereof is omitted here.

(Color Electrophotographic Image Forming Apparatus)

FIG. 12 is a cross-sectional view of a color electrophotographic imageforming apparatus main body (hereinafter, referred to as an apparatusmain body) 100 of this embodiment. Four electrophotographicphotosensitive drums (hereinafter, referred to as drums) 310 (310Y,310M, 310C, 310K) are arranged side-by-side in a center portion of theapparatus main body 100. Cartridges 50 (50Y, 50M, 50C, 50K) containingtoner of a yellow color, a magenta color, a cyan color, and a blackcolor are detachably mounted onto the respective drums 310. Theapparatus main body 100 refers to a configuration in which thecartridges 30 and 50 are removed from an image forming apparatus 300. Ascanner unit 20 is disposed above the drums 310 and irradiates therespective drums 310 with laser light LY, LM, LC, and LK for formingelectrostatic latent images. A transfer portion 70 is disposed below thedrums 310, and a cassette 81 containing paper 82 as a recording mediumis disposed below the transfer portion 70.

Hereinafter, each portion will be described in detail. This embodimentuses the same sheet feed portion 8, fixing portion 9, and deliveryportion 10 as those in Embodiment 1, and hence the description thereofis omitted.

(Process Cartridge)

Each of the process cartridges 30 (30Y, 30M, 30C, 30K) incorporatesintegrally the electrophotographic photosensitive drum 310 and acharging member 40 and a cleaning member 610, which are process meansacting on the drum 310, in a process frame 301 (301Y, 301M, 301C, 301K).Further, the cartridge 30 of this embodiment has a removed tonercontaining portion 620 containing toner removed from the drum 310 by thecleaning member 610. The drum 310 has a photosensitive layer made of anorganic photoconductor on the surface of a cylinder, and is supportedrotatably by the process frame 301 and rotated in the clockwisedirection during driving.

(Developing Cartridge)

Each of the developing cartridges 50 (50Y, 50M, 50C, 50K) has a tonercontaining portion 520 containing toner of a yellow color, a magentacolor, a cyan color, or a black color, a developing roller 51 asdeveloping means, and a developing frame 530 that rotatably supports thedeveloping roller 51 and integrates the toner containing portion 520.The cartridge 50Y contains yellow toner in the toner containing portion520Y. The cartridge 50M contains magenta toner in the toner containingportion 520M. The cartridge 50C contains cyan toner in the tonercontaining potion 520C. The cartridge 50K contains black toner in thetoner containing portion 520K.

(Transfer Portion)

The transfer portion 70 has a transfer belt (intermediate transfermember) 710, a primary transfer roller 720, a secondary transfer opposedroller 730, a transfer driving roller 740, and a secondary transferroller 750.

(Replacement of a Cartridge)

Next, the replacement of the cartridges 30 and 50 will be described. Thedrum 310, the charging member (process means) 40, and the cleaningmember (process means) 610 of the cartridge 30 are degraded as the imageforming operation is repeated. Further, the toner containing portion 520cannot collect toner any more once it has collected a predeterminedamount of removed toner. That is, the cartridge 30 reaches the end ofthe service life thereof when the image forming operation is repeatedpredetermined times. More specifically, an image of quality thatsatisfies users cannot be formed any more. When the cartridge 30 reachesthe end of the predetermined service life thereof, a satisfactory imageforming operation can be performed again by replacing the cartridge 30by a new one. Likewise, the cartridge 50 also needs to be replaced by anew one when it reaches the end of the service life thereof due to thedegradation of the developing roller 51 and the consumption of tonercontained in the toner containing portion 520.

(Tray Member)

The cartridges 30 and 50 are detachably mounted onto a tray 13 that is acartridge mounting portion for the cartridges 30, 50. The tray(cartridge mounting portion) 13 corresponds to a process cartridgemounting portion and a developing cartridge mounting portion (cartridgemounting portion). That is, the both the cartridges 30 and 50 aresupported by the tray 13. In the tray 13, mounting portions 13 a onwhich the cartridges 30 are detachably mounted and mounting portions 13b on which the cartridges 50 are detachably mounted are providedalternately in a longitudinal direction of the tray 13. For replacingboth the cartridges 30, 50, as illustrated in FIG. 13, the cover 110 isopened, and the tray 13 is taken out from the apparatus main body 100.Then, the cartridges 30, 50 are replaced under the condition that thetray 13 is pulled out from the apparatus main body 100. Note that FIG.14 illustrates the state in which the tray (cartridge mounting portion)13 is pulled out from the apparatus main body 100. In this state, theattachment and detachment of the cartridges 30, 50 with respect to thetray (cartridge mounting portion) 13 are performed. The tray 13 may beremoved from the apparatus main body 100 when the paper 82 jammed in theapparatus main body 100 is taken out from the apparatus main body 100(FIG. 14). In this case, a stopper (not shown) restricting the tray 13from being pulled out from the apparatus main body 100 more than apredetermined amount is released. As described above, the apparatus mainbody 100 corresponds to a configuration in which the cartridges 30, 50are removed from the image forming apparatus 300, and the tray 13 isalso included in the apparatus body 100.

FIG. 14 illustrates the state in which the tray 13 has been taken outfrom the apparatus main body 100 and further all the cartridges 30, 50mounted onto the tray 13 have been taken out. On inner walls of sideplates 131 of the tray 13, there is a guide groove (main body side guideportion) 132 that is a main body side (tray side) guide for regulatingthe movement locus of the cartridge 30 when the cartridge 30 is mountedand detached from the tray 13 and a guide groove (main body side guideportion) 133 that is a main body side (tray side) guide for regulatingthe movement locus of the cartridge 50 when the cartridge 50 is mountedand detached from the tray 13. The cartridge 30 is guided by the guidegroove 132 when being mounted and detached from the tray 13. Thecartridge 50 is guided by the guide groove 133 when being mounted anddetached from the tray 13.

(Process Cartridge Side Guide Portion)

FIG. 15A is a perspective view of the cartridge 30. The cartridge 30 ismounted in a mounting direction indicated by the arrow α under thecondition that the drum 310 is exposed. The mounting direction α isorthogonal to the longitudinal direction of the drum 310. At both endsin the longitudinal direction of the process frame 301, as illustratedin FIG. 15A, there is provided a guide 320, which is a process cartridgeside guide portion that is engaged with the guide groove 132 during themounting and detaching of the cartridge 30 to regulate the movementlocus of the cartridge 30. Further, a leading edge in the mountingdirection α of the guide 320 (first process cartridge side guideportion) has a protruding portion (second process cartridge side guideportion) 320 a protruding further than the leading edge 310 a of thedrum 310.

(Developing Cartridge Side Guide Portion)

FIG. 15B is a perspective view of the cartridge 50. The cartridge 50 ismounted in a mounting direction indicated by the arrow β under thecondition that the developing roller 51 is exposed. The mountingdirection β is orthogonal to the longitudinal direction of thedeveloping roller 51. At one end and the other end in the longitudinaldirection of the developing frame 530, as illustrated in FIG. 15B, aguide 540 is provided. The guide 540 is a developing cartridge sideguide portion that is engaged with the guide groove 133 during themounting and detaching of the cartridge 50 with respect to the tray 13to regulate the movement locus of the cartridge 50. Further, a leadingedge in the mounting direction β of the guide 540 has a protrudingportion 540 a protruding on the downstream side in the mountingdirection β further than the leading edge 51 b of the developing roller51.

(Mounting Operation of a Cartridge with Respect to a Tray)

Next, a method of mounting the cartridges 30, 50 on the tray 13 will bedescribed with reference to FIGS. 16 and 17. In the description, it isassumed that a process cartridge to be replaced is the cartridge 30Mpaired with the cartridge 50M and a developing cartridge to be replacedis the developing cartridge 50C of cyan. The cartridges 30 and 50 can berespectively replaced independently. Thus, the cartridges 30Y, 30C, 30Kand the cartridges 50Y, 50M, 50K that are not required to be replacedhave already been mounted onto the tray 13.

As illustrated in FIG. 16, guide grooves 132M provided on the sideplates 131 of the tray 13 are adapted to receive process cartridge sideguides 320M, respectively. Further, guide grooves 133C are adapted toreceive developing cartridge side guides 540C. As illustrated in FIG.17, the cartridge 30M is mounted in the direction indicated by the arrowα from above the tray 13 with the drum 310M directed downward. First,the guides 320M and the guide grooves 132M are aligned, and then, thecartridge 30M is inserted into the tray 13. If the guide 320M is notaligned with the guide groove 132M, the protruding portion 320 a of theguide 320M comes into contact with the side plate 131. Therefore, thecartridge 30M cannot be inserted any more. At this time, the protrudingportion 320 a of the guide 320M protrudes on the downstream side in themounting direction α further than the leading edge 310 a of the drum310M. Therefore, the drum 310M does not come into contact with the tray13 to damage the drum 310M. When the guides 320M are aligned with theguide grooves 132M respectively and the cartridge 30M is inserted intothe tray 13, the movement locus during the mounting of the cartridge 30Mis regulated by the engagement between the guides 320M and the guidegrooves 132M. That is, when the drum 310M passes through the adjacentdeveloping frames 530Y, 530M and the opening 131 a provided on the sideplate 131 of the tray 13, the mounting locus of the cartridge 30M hasalready been regulated. Therefore, the drum 310M can be mounted onto thetray 13 without damaging the drum 310M. The cartridge 50C is mounted inthe mounting direction indicated by the arrow β toward an opening 131 bdefined by the process frame 301C, the process frame 301K, and the sideplates 131. At this time, in the same way as in the description of themethod of mounting a cartridge, when the developing roller 51C passesthrough the opening 131 b, the movement locus of the cartridge 50C isregulated by the engagement between the guides 540C and the guidegrooves 133C. Thus, the cartridge 50C can be mounted onto the tray 13without bringing the developing roller 51C into contact with the tray 13to damage the developing roller 51C. Note that, when the cartridge 30Mand the cartridge 50C are taken out of the tray 13, respectively, theoperation opposite to the above-mentioned mounting operation should beperformed. In this manner, according to this embodiment, a user pushesthe tray 13 into the main body 100 under the condition that thecartridges 30, 50 are supported by (mounted onto) the tray 13, wherebythe cartridges 30, 50 are mounted at image forming positions of theapparatus main body 100. Further, the user pulls out the tray 13 fromthe main body 100 under the condition that the cartridges 30, 50 aresupported by the tray 13, whereby the cartridges 30, 50 can be taken outfrom the apparatus main body 100. Note that, regarding the configurationin which the cartridges 30, 50 are positioned at the image formingpositions of the apparatus main body 100 by pushing the tray 13 into theinside of the main body 100, a known configuration can be appliedappropriately.

Note that, in this embodiment, the main body side guide portions are theguide grooves 132 and 133 provided on the side plate 131 of the tray 13.Further, the cartridge side guide portions are the guide members 320 and540 that have an elongated shape in the mounting directions α and β inwhich the cartridges 30 and 50 are mounted onto the tray 13 and thatprotrude outward from the frames 301 and 530. Thus, the cartridges 30and 50 are guided to the predetermined mounting portions 13 a and 13 bunder the condition that the upstream side and the downstream side inthe pull-out direction of the tray 13 of the guide members 320 and 540are regulated by the guide grooves 132 and 133, i.e., under thecondition that the movement loci thereof are regulated. However, thisembodiment is not limited thereto. For example, the cartridge side guideportion may be a groove, and the main body side guide portion may be aprotruding portion. Even in this case, the cartridges 30 and 50 areguided to the predetermined mounting portions 13 a and 13 b under thecondition that the upstream side and the downstream side in the pull-outdirection thereof are regulated, i.e., under the condition that themovement loci thereof are regulated. Further, for example, the cartridgeside guide portion may be a protruding portion, and the main body sideguide portion may be a protruding portion. In this case, the cartridges30 and 50 are guided by the predetermined mounting portions 13 a and 13b under the condition that the protruding portion as a cartridge sideguide portion is supported by the protruding portion as a main body sideguide portion. In such a case, the cartridges 30 and 50 are guided tothe predetermined mounting portions 13 a and 13 b under the conditionthat the movement to either the upstream side or the downstream side inthe pull-out direction is regulated, i.e., under the condition that themovement loci thereof are regulated.

As described above, according to this embodiment, in the image formingapparatus of the 1-pass system, in the case where the cartridge 30integrally incorporating the drum and the process means acting on thedrum is mounted and detached from the tray (cartridge mounting portion)13, when the drum moves in the tray 13, the movement locus of thecartridge 30 is regulated. Therefore, the cartridge 30 can be replacedwithout bringing the drum into contact with the tray 13 to damage thedrum.

In this embodiment, the configuration in which the protruding portion320 a of the guide 320 protrudes on the downstream side in the mountingdirection α further than the leading edge 310 a of the drum 310 has beendescribed. However, according to this embodiment, as illustrated in FIG.18A, the protruding portion 330 may be provided in the process frame 301of the cartridge 30. That is, as illustrated in FIG. 18A, the protrudingportion 320 a is disposed so that the protruding portion 330 protrudesin the mounting direction α from the drum 310. When the cartridge 30 ismounted onto the apparatus main body, even if an attempt is made toinsert the cartridge 30 into the tray 13 (apparatus main body 1) underthe condition that the guide groove 132 is not aligned with the processcartridge guide 320 that is a first process cartridge side guideportion, the protruding portion 330 comes into contact with the innerwall of the apparatus main body 100 or the process cartridge or thedeveloping cartridge mounted adjacent thereto, and hence thephotosensitive drum can be prevented from being damaged. Further, theprotruding portion (second process cartridge side guide portion) 330 maybe provided with a guide function of being engaged with the processcartridge guide groove 132 to regulate the movement locus of the processcartridge 30. As illustrated in FIG. 18B, the second process cartridgeside guide portion 320 a as a protruding portion that protrudes in themounting direction α further than the drum 310 may be provided in theprocess cartridge guide 320 that is the first process cartridge sideguide portion. In the embodiment illustrated in FIG. 15A, the protrudingportion 320 a is integrated with the process cartridge guide 320.However, the protruding portion 320 a may be provided separately fromthe process cartridge guide 320, as illustrated in FIG. 18B. Theprotruding portion 320 a serves as a second guide portion for guidingthe process cartridge. Thus, according to this embodiment, the guidemember 320 (320 a) has a protrusion length capable of preventing thedrum 310 from coming into contact with the tray 13 (member on the mainbody 1 side) in the case where the cartridge 30 is mounted onto the tray13 under the condition that the above-mentioned alignment has not beenperformed. In addition, the guide members 320 (320 a) are provided atone end side and the other end side of the drum 310 where the guidemembers 320 (320 a) can prevent the drum 310 from coming into contactwith the member on the main body 1 side. Herein, the member on theapparatus main body 1 side may be, for example, the tray (cartridgemounting portion) 13 provided in the apparatus main body 1. Further, theguide 540 (540 a) has a protrusion length capable of preventing thedeveloping roller 51 from coming into contact with the tray 13 (memberon the main body 1 side) when the cartridge 50 is to be mounted onto thetray 13. In addition, the guide members 540 (540 a) are provided at oneend side and the other end side of the developing roller 51 where theguide members 540 (540 a) can prevent the developing roller 51 fromcoming into contact with the member on the main body 1 side. Herein, themember on the apparatus main body 1 side may be, for example, the tray(cartridge mounting portion) 13 provided in the apparatus main body 1.

Embodiment 4

Further, in the configuration illustrated in Embodiment 3, asillustrated in FIG. 19, a guide member may be movable between theprotruding position and the retracted position, and further providedwith a locking portion as illustrated in Embodiment 2. As illustrated inFIG. 19, the tray (cartridge mounting portion) 13 has process cartridgemounting portions and developing cartridge mounting portions (cartridgemounting portions). Multiple cartridges 30 can be mounted side-by-sidein the horizontal direction and detached from the process cartridgemounting portions 13 a of the tray 13. The cartridge 30 is detachablymounted onto the mounting portion 13 a with the photosensitive drum 310being a leading edge. Further, multiple developing cartridges 50 can bemounted side-by-side in the horizontal direction and detached from thedeveloping cartridge mounting portions 13 b of the tray 13. Thecartridge 50 is detachably mounted onto the mounting portion 13 b withthe developing roller 51 being a leading edge. On the tray 13, themounting portions 13 a and the mounting portions 13 b are providedalternately in the longitudinal direction of the tray 13. In the guidegrooves (main body side guide portions) 132 (132Y, 132M, 132C, 132K)provided on the inner wall of the tray 13, protruding portions 1321(1321Y, 1321M, 1321C, 1321K) serving as abutting portions and engagementportions are provided, and in the guide grooves 133 (main body sideguide portions) (133Y, 133M, 133C, 133K), protruding portions 1331(1331Y, 1331M, 1331C, 1331K) serving as abutting portions and engagementportions are provided.

Hereinafter, the cartridge 30M will be described. The other cartridgesalso have the same configuration as that of the cartridge 30M, and hencethe description thereof is omitted. Each of process cartridge side guideportions 340M provided at one end and the other end in the longitudinaldirection (longitudinal direction of the drum 310) of the cartridge 30Mis provided with a cam 341M. The guide portion 340M protrudesretractably on the downstream side further than the leading edge 310 aof the drum 310 in the mounting direction in which the cartridge 30M ismounted onto the mounting portion 13 a of the tray 13. The cam 341M is alocking portion that locks the guide portion 340M when the guide portion340M moves to the retracted position. The process frame 301 is providedwith a lock hole 3011M with which the cam 341M is engaged. Further, inthe same way as in Embodiment 2 illustrated in FIG. 8, the cartridge 30has a guide spring (elastic member) (not shown) urging the guide 340M ina protruding position direction and a cam spring (elastic member) (notshown) urging the cam 341M in the rotation direction.

Hereinafter, the developing cartridge 50C will be described. The othercartridges also have the same configuration as that of the developingcartridge 50C, and hence the description thereof is omitted. Each ofdeveloping cartridge side guides 550C provided at one end and the otherend in the longitudinal direction (longitudinal direction of thedeveloping roller 51) of the cartridge 50C is provided with a cam 551C.The cam 551C is a locking portion that locks the guide 550C when theguide 550C moves to the retracted position. A developing frame 530C isprovided with a lock hole 5301C with which the cam 551C is engaged. Inthe same way as in Embodiment 2 illustrated in FIG. 8, a guide spring(elastic member) (not shown) urging the developing cartridge side guide550C toward the protruding position, and a cam spring (elastic member)(not shown) urging the cam 551 to the rotation direction are provided.The description regarding those operations is omitted since they aresimilar to those in Embodiment 2.

With the configuration of the cartridge 30, the guide portion 340 can bemoved to the retracted position when the cartridge 30 is mounted ontothe tray 13. Similarly, when the cartridge 50 is mounted onto the tray13, the guide portion 550 can be moved to the retracted position. Thus,the guide grooves 132, 133 provided on the tray 13 can be shortenedcompared with the respective guide grooves illustrated in Embodiment 3.This can downsize the tray 13. Further, a pressing member (elasticmember) (not shown) pressing the cartridge 30 to the transfer belt 710may be provided. The pressing member presses the cartridge 30 so thatthe electrophotographic photosensitive drum 310 is directed to atransfer belt 710 onto which a developer image formed on theelectrophotographic photosensitive drum 310 is transferred. Thus, whenthe cartridge 30 is mounted onto the apparatus main body 100, thepressing force of the drum 310 pressing the transfer belt is keptappropriately. Further, when the cartridge 30 is pressed by the pressingmember, the guide portion 340 is locked at the retracted position by thecam (locking portion) 341.

Note that, even in this embodiment, the arrangement, the protrusionlength, and the like of the guide member may be determined in the sameway as in Embodiment 3 described above.

As described above, according to an embodiment of the present invention,a further downsized image forming apparatus can be provided.

Further, according to the embodiment of the present invention, it ispossible to provide an image forming apparatus and a developingcartridge capable of reducing the possibility that, when the developingcartridge is mounted onto a developing cartridge mounting portion, adeveloping roller of the developing cartridge to be mounted comes intocontact with a member on an apparatus main body side.

Further, according to the embodiment of the present invention, it ispossible to provide an image forming apparatus and a developingcartridge capable of reducing the damage of a developing roller at atime of replacement of the developing cartridge.

Further, according to another embodiment of the present invention, it ispossible to provide an image forming apparatus and a process cartridgecapable of reducing the possibility that, when the process cartridge ismounted onto a process cartridge mounting portion, a photosensitivemember of the process cartridge to be mounted comes into contact with amember on an apparatus main body side.

Further, according to another embodiment of the present invention, it ispossible to provide an image forming apparatus and a process cartridgecapable of reducing the damage of a photosensitive member at a time ofreplacement of the process cartridge.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2009-057447, filed Mar. 11, 2009, which is hereby incorporated byreference herein in its entirety.

1. A developing cartridge detachably mountable to an electrophotographicimage forming apparatus main body having main body side guide portionsand a developing cartridge mounting portion to which a plurality ofdeveloping cartridges are detachably mountable side-by-side, thedeveloping cartridge comprising: a developer containing portion forcontaining a developer; a developing roller for developing anelectrostatic latent image formed on an electrophotographicphotosensitive member using the developer; first developing cartridgeside guide portions provided at one end and the other end, respectively,in a longitudinal direction of the developing roller, for engaging withthe main body side guide portions to regulate a movement locus of thedeveloping cartridge when the developing cartridge is mounted to theelectrophotographic image forming apparatus main body; and protrudingportions provided at the one end and the other end, respectively, in thelongitudinal direction of the developing roller, wherein the developingcartridge is mounted to the electrophotographic image forming apparatusmain body in a mounting direction intersecting with the longitudinaldirection of the developing roller with the developing roller being aleading edge, and wherein the protruding portions protrude on adownstream side further than the developing roller in the mountingdirection. 2-18. (canceled)
 19. A developing cartridge according toclaim 1, wherein the protruding portions are second developing cartridgeside guide portions for engaging with the main body side guide portionsto regulate the movement locus of the developing cartridge when thedeveloping cartridge is mounted to the developing cartridge mountingportion.
 20. A process cartridge detachably mountable to anelectrophotographic image forming apparatus main body having main bodyside guide portions and a process cartridge mounting portion to which aplurality of process cartridges are detachably mountable side-by-side,the process cartridge comprising: an electrophotographic photosensitivedrum; first process cartridge side guide portions provided at one endand the other end, respectively, in a longitudinal direction of theelectrophotographic photosensitive drum, for engaging with the main bodyside guide portions to regulate a movement locus of a process cartridgewhen the process cartridge is mounted to the electrophotographic imageforming apparatus main body; and protruding portions provided at the oneend and the other end, respectively, in the longitudinal direction ofthe electrophotographic photosensitive drum, wherein the processcartridge is mounted to the electrophotographic image forming apparatusmain body in a mounting direction intersecting with the longitudinaldirection of the electrophotographic photosensitive drum with theelectrophotographic photosensitive drum being a leading edge, andwherein the protruding portions protrude on a downstream side furtherthan the electrophotographic photosensitive drum in the mountingdirection.
 21. A process cartridge according to claim 20, wherein theprotruding portions are second process cartridge side guide portions forengaging with the main body side guide portions to regulate the movementlocus of the process cartridge when the process cartridge is mounted tothe process cartridge mounting portion.
 22. An electrophotographic imageforming apparatus to which a plurality of developing cartridges aredetachably mounted for forming an image on a recording medium, theelectrophotographic image forming apparatus comprising: main body sideguide portions; and a developing cartridge mounting portion to which theplurality of developing cartridges are detachably mounted side-by-side,each of the plurality of developing cartridges comprising: a developercontaining portion for containing a developer; a developing roller fordeveloping an electrostatic latent image formed on anelectrophotographic photosensitive member using the developer; firstdeveloping cartridge side guide portions provided at one end and theother end, respectively, in a longitudinal direction of the developingroller, for engaging with the main body side guide portions to regulatea movement locus of a developing cartridge when the developing cartridgeis mounted to an electrophotographic image forming apparatus main body;and protruding portions provided at the one end and the other end,respectively, in the longitudinal direction of the developing roller,wherein the developing cartridge is mounted to the electrophotographicimage forming apparatus main body in a mounting direction intersectingwith the longitudinal direction of the developing roller with thedeveloping roller being a leading edge, and wherein the protrudingportions protrude on a downstream side further than the developingroller in the mounting direction.
 23. An electrophotographic imageforming apparatus according to claim 22, wherein the protruding portionsare second developing cartridge side guide portions for engaging withthe main body side guide portions to regulate the movement locus of thedeveloping cartridge when the developing cartridge is mounted to thedeveloping cartridge mounting portion.
 24. An electrophotographic imageforming apparatus to which a plurality of process cartridges aredetachably mounted for forming an image on a recording medium, theelectrophotographic image forming apparatus comprising: main body sideguide portions; and a process cartridge mounting portion to which theplurality of process cartridges are detachably mounted side-by-side,each of the plurality of process cartridges comprising: anelectrophotographic photosensitive drum; first process cartridge sideguide portions provided at one end and the other end, respectively, in alongitudinal direction of the electrophotographic photosensitive drum,for engaging with the main body side guide portions to regulate amovement locus of a process cartridge when the process cartridge ismounted to an electrophotographic image forming apparatus main body; andprotruding portions provided at the one end and the other end,respectively, in the longitudinal direction of the electrophotographicphotosensitive drum, wherein the process cartridge is mounted to theelectrophotographic image forming apparatus main body in a mountingdirection intersecting with the longitudinal direction of theelectrophotographic photosensitive drum with the electrophotographicphotosensitive drum being a leading edge, and wherein the protrudingportions protrude on a downstream side further than theelectrophotographic photosensitive drum in the mounting direction. 25.An electrophotographic image forming apparatus according to claim 24,wherein the protruding portions are second process cartridge side guideportions for engaging with the main body side guide portions to regulatethe movement locus of the process cartridge when the process cartridgeis mounted to the process cartridge mounting portion.